In a distributed network environment where there are numerous servers each providing access to a particular service or device, there may be a central manager residing on a server that has been designated the task to collect information with regard to the available services and/or devices on the network and to make this information available to servers within the network. FIG. 1 illustrates such a network topology wherein a network 10 connects a number of servers 12, 14, 16, 18, and 20. Each server may in term be connected to other devices such as a scanner 22, a printer 24, a fax machine 26, or a plotter 28, or itself may be the service and/or operative device (e.g., disk array file server 12) at a particular network node. Each server connected to the network will have a unique network address, node name, and port number, and can be accessed accordingly. Additionally, each server has an agent responding to requests from other servers.
The task in collecting information with regard to available agents on the network is made complicated by the fact that agents and the associated services and/or devices may become unavailable due to a variety of possible causes, and new agents (and the associated services and/or devices) may be added to the network on an on-going basis as well. Given the dynamic nature of the environment, it becomes important to have an automated, efficient, and compatible method for determining the available agents on a network at any one time.
In prior art technologies, several methods were used to determine and maintain a list of the available agents. In the simplest method, a static list is maintained on a server, and changes to the list have to be manually carried out. This method is not practical in large, complex network environments and is tedious at best. In another prior art technology using a broadcast approach, a server sends a broadcast out to the network requesting any and all available agents to respond and register with the requesting server. However, this approach is only available with certain hierarchical network topology using proprietary protocol. Additionally, this approach generates a great deal of overhead in the broadcast itself because such a blind attempt to communicate with agents on all possible addresses and port numbers consumes an unacceptable level of CPU cycle time and has proven to be unreliable in registering all available agents. In yet another prior art technology, proprietary network protocol is setup in such a manner as to require that each of the agents check-in with a designated server at specified intervals. With this approach, each of the agents would have to be programmed to perform the registration function before it is registered with the network. This method requires an additional layer of compatibility and protocol, and thereby increases the cost associated with this task.
Ideally, it would be desirable to have a non-proprietary method for accomplishing automatic registration of available agents on a distributed network with this task being performed by any server.